Hard disk drives (“HDDs”) are widely used to store digital data or electronic information for enterprise data processing systems, computer workstations, portable computing devices, digital audio players, digital video players, and the like. Generally, HDDs store data on a disk with a layer of magnetic material. A transducer head, e.g., read-write head, includes a writing component that magnetically polarizes areas or bits of the magnetic material with one or two polarities to encode either binary zeros or ones. Thus, data is recorded as magnetically encoded areas or bits of magnetic polarity. The direction of the magnetization points in different directions, which can be referred to as a positive state and a negative state. Each bit can store information (generally binary information in the form of either a 1 or a 0) according to the magnetic polarization state of the bit. Typically, bits are arranged along respective radially-adjacent (e.g., concentric) annular tracks of a disk. A single disk can include space for millions of tracks each with millions of bits. A transducer head also includes a reading component that detects the magnetic polarity of each bit or area and generates an electrical signal that approximates the magnetic polarity. The signal is processed to recover the binary data recorded on the magnetic material.
The disks of an HDD rotate as transducer heads hover over the respective disks to read data from and write data to the disks. Rotation of the disks is driven by a spindle motor that is rotatably coupled to the disks via a central spindle. The position of the transducer heads relative to the disks, and the location on the disks from which data is read or to which data is written, is controlled via actuation of an actuator. The actuator controls the movement of the plurality of armatures each securing a respective one of the transducer heads. As the disks rotate, the actuator actuates to rotate the armatures and move the transducer heads radially inwardly or outwardly over the disks.
The dynamic performance of an HDD is a major mechanical factor for achieving higher data capacity as well as for manipulating the data faster. The quantity of data tracks recorded on the disk surface is determined partly by how well the transducer heads and a desired data track can be positioned relative to each other and made to follow each other in a stable and controlled manner. There are many factors that can influence the ability of an HDD to perform the function of positioning the transducer heads and following the data track with the heads. One such factor is undesirable motions that can come about through unwanted vibrations of components of the HDD.